SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e139a05d5490c478183996fbec785014120958334ae7d0909cd37350e89f3d' 
  AND token = 'JRsP5aMkKSmveY5RCaqhrBlLCDtXSb1+8QC1wIEVRZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}